The present invention relates to an MRI (Magnetic Resonance Imaging) apparatus, and more particularly to an MRI apparatus capable of recreating a diffusion tensor image in a short period of time where an abnormal image exists.
There has heretofore been known an MRI apparatus which obtains sets of diffusion weighted images of six or more axes by photography or imaging and creates an intended diffusion tensor image from the sets of the diffusion weighted images (refer to, for example, patent documents 1 and 2).
Patent Document 1. Japanese Unexamined Patent Application Publication No. 2005-525208.
Patent Document 2. Japanese Unexamined Patent Publication No. Hei 9(1997)-70397.
When a diffusion tensor image is created from sets of diffusion weighted images of nine axes, for example, imaging or photography free of application of an MPG (Motion Probing Gradient) is done once and the MPG is applied to the nine axes respectively, and their imaging is done to obtain the sets of diffusion weighted images of the nine axes. Therefore, it is necessary to carry out photographs of 10 times (=1+9) as a whole.
On the other hand, since the diffusion weighted imaging or photography executed by application of the MPG is sensitive to motion, the diffusion weighted image might be an improper abnormal image due to fine motion of a subject. A diffusion tensor image created from a set of diffusion weighted images including the abnormal image might also be an improper abnormal image.
In the conventional MRI apparatus, the diffusion weighted imaging about all axes was redone even when the abnormal image occurred in one axis. That is, when the diffusion tensor image is created from the sets of the diffusion weighted images of the nine axes as in the example referred to above, the diffusion tensor image has been recreated based on the diffusion weighted images obtained by retrying ten photographs.
Under such circumstances, however, a problem arises in that it results in a reduction in detection efficiency.